1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a liquid crystal display device having a digitizer.
2. Description of Related Art
Liquid crystal display (LCD) panels are used in many electronic data handling devices, including lap-top computers, personal digital assistants, personal organizers, and point-of-sale terminals. These flat panel display systems typically incorporate the capability of inputting information directly onto the display screen by pointing or writing with a finger or a non-inking pen. For example, a finger may be used to push a “soft” button that is displayed on the screen or a non-inking stylus can be used to sign one's name and have it captured and displayed electronically.
A typical LCD panel, as shown in FIG. 1, comprises a liquid crystal display (LCD) module “L” and a digitizer “D”. The LCD module “L” has lower and upper substrates 10 and 20 with a liquid crystal layer 13 interposed therebetween. The lower substrate 10 has switching elements (not shown) such as thin film transistors (TFTs), and the upper substrate 20 has a common electrode, color filter and black matrix. A linear polarizer 22 is located on the upper substrate. The two lower and upper substrates 10 and 20 are sealed by a sealant 12, thus preventing leakage of the liquid crystal. Further, pads (not shown) patterned on the lower substrate 10 are electrically coupled to a printed circuit board (PCB) 14 through a TCP (tape carrier package) 17 having a film 18 where a drive integrated circuit (IC) 19 is mounted. Pads (not shown) on the lower substrate 10 and output signal lines of the film 18 are electrically connected with anisotropic conductive film 16a, and signal lines of the PCB 14 and input lines of the film 18 are electrically connected with anisotropic conductive film 16b. 
Further, the digitizer “D” as a location-sensing component has first and second plates 24 and 26 and a drive circuit 25 (see FIG. 4), and the two plates 24 and 26 serve to produce or detect signals indicative of the location of a pen, a finger or other input devices. Each of the two plates 24 and 26, even though not shown, has a substrate, a transparent electrode and a metal pattern layer, which are stacked in the above-described order. Further, as shown in FIG. 2 which is a plan view of the first plate 24 of the digitizer “D”, the first plate 24 of the digitizer “D” has a plurality of digitizer electrodes 28 formed along the edges of an active region 32 and regularly spaced apart from each other. The digitizer electrodes 28 are connected to an external digitizer drive circuit (not shown). The active region 32 is a location sensing region and has a resistive layer in the form of a strip or a grid.
Further, the drive circuit 15 for the LCD module “L”, as shown in FIG. 3, comprises a power supply 15a for supplying a voltage, a clock generator 15b for producing clock signals to drive the LCD device, a gamma circuit 15c for collecting a gamma characteristic of the LCD device, a controller 15d for controlling all components of the LCD module “L”, and data and gate drivers 15e and 15f for producing images. Further, the drive circuit 25 for the digitizer “D”, as shown in FIG. 4, comprises a power supply 25a for supplying a voltage, a clock generator 25b for producing clock signals to drive the digitizer, a controller 25c for controlling all components of the digitizer “D”, and an analog to digital (A/D) converter 25d for converting analog signals to digital signals, an input/output (I/O) unit 1 25e for conveying analog signals from the digitizer to the A/D converter 25f and conveying signals from the controller 25d to the digitizer, and an input/output (I/O) unit 2 25e for transferring digital signals in the form of x and y coordinate values from the A/D converter 25f to a main system of the device having the LCD device such as notebook computer by the controller 25d. 
However, the LCD panel described above has the following disadvantages. First, as shown in FIG. 2, since a plurality of wires 30 are directed toward just one direction for connection with the external drive circuit 25, each wires 30 differs in length, thereby causing different RC delays. Secondly, as shown in FIGS. 3 and 4, the digitizer “D” and the liquid crystal display module “L” use different drive circuit boards 14 and 25 even though they have the same elements such as a power supply, controller and clock generator, whereupon a production cost of the LCD device with digitizer is very high and it is also very difficult to achieve a compact LCD panel.